Preparation of glycol molybdate complexes



United States Patent C 3,285,942 PREPARATION OF GLYCOL MOLYBDATE COMPLEXES John A. Price, Westfield, and Richard F. Neblett, Plainfield, N.J., assignors to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Filed Mar. 6, 1962, Ser. No. 177,738 10 Claims. (Cl. 260429) This invention concerns an improved process for the manufacture of organic complexes containing molybdenum. These complexes are derived by reaction of molybdic acid or a related compound with organic hydroxy compounds, particularly glycols. Such complexes are useful as addition agents for lubricating oil compositions wherein they serve as wear-reducing agents and in some cases may function also as inhibitors of oxidation and/ or corrosion.

It has been known for some time that various molybdenum compounds, and particularly molybdenum sulfide or complexes either containing molybdenum sulfide or capable of forming molybdenum sulfide during use, are desirable additives for lubricating oils because of their ability to reduce friction and hence to minimize wear of the parts being lubricated. It has recently been found as disclosed in copending application S.N. 130,263 of John A. Price, filed Aug. 9, 1961, and now abandoned, that desirable antiwear properties can be incorporated into a lubricating oil composition by adding to such a composition a combination of a particular type of organic sulfur compound and a complex or ester that is derived by the reaction of molybdic acid or a related material such as M ammonium molybdate, ammonium paramolybdate, or a molybdenum halide such as MoCl with an alphaor beta-alkane diol. The sulfur compounds are those that contain labile sulfur that can become available for reaction with the molybdenum to form molybdenum sulfide.

The reaction of glycols with molybdic acid yields complexes of the type wherein R R and R are hydrogen atoms or alkyl groups. Suitable glycols that may be used are selected from the group consisting of alphaand beta-alkane diols of from 2 to 18 carbon atoms. Specific glycols that may be used include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-pentanediol, 2,3-butanediol, 1,2-hexanediol, 2-methyl-l,3-pentanediol, 2-ethylhexane-1,3-diol, other 1,2- or 1,3-octylene glycols, 1,2-dodecanediol, 2,4-diethyloctane-1,3-diol, and 2,4,6-trietl1yldecane-1,3-diol.

In preparing glycol molybdates by reaction of glycols 3,285,942 Patented Nov. 15, 1966 with moly'bdic acid or related molybdenum compounds, large excesses of the glycol are ordinarily required in order that the molybdic acid reagent will be utilized to a satisfactory extent. In most cases, the excess glycol amounts to some 200 to 250 percent above the stoichiometric quantity. This excess glycol must then be recovered from the product either by extraction or by a high-temperature, low-pressure distillation. Manifestly, this recovery or removal of the excess glycol adds considerably to the cost of the process. There thus has been a need for improving the efiiciency of the reaction of a glycol with molybdic acid.

In accordance with the present invention, it has been found that organic nitrogen bases are very effective catalysts for the reaction of glycols with molybdic acid. These bases are selected from the group consisting of alkyl amines of at least 6 carbon atoms, aryl amines, amides, azines and oxazines, having boiling points not exceeding about 300 C. at atmospheric pressure. When using these catalysts the reaction can be carried further to completion and only a small excess of glycol is required.

The nitrogen bases employed in the present invention include: N-dialkyl amides such as dimethyl. formamide, dimethyl acetamide, and diethyl formamide; dialkylamines such as diamyl amine, di-iso-octyl amine, and dibenzyl amine; trialkylamines such as triethylamine; aryl amines including aniline, toluidine, phenylene diamine, xylidine, and N-alkylated or N-arylated derivatives; azines such as pyridine, pyrazine, diazo bicyclo octane, piperidine and N-ethyl piperidine; and oxazines, including morpholine and N-ethyl morpholine.

The reaction of the glycol with the molybdic acid or related compound is preferably conducted at a temperature in the range of from about to C. in an aromatic hydrocarbon solvent such as benzene, toluene, xylene or the like. The reaction is conveniently conducted under reflux and the water of reaction is separated from the reflux stream. It is preferred that the mole ratio of glycol to molybdic acid be within the range of from 1 to 1 to 1.25 to 1. Based on the ammonium rnolybdate or equivalent molybdenum compound used in the reaction, the concentration of nitrogen base catalyst will be in the range of from 1 to 50 weight per cent, the preferred range being from about 10 to 40 Weight per cent. The catalyst is removed from the reaction product along with the solvent by distillation under reduced pressure.

The following examples serve to illustrate the nature of this invention, the manner in which it may be practiced, and the advantages accruing from the use of the catalysts.

EXAMPLE 1 A typical preparation utilizing the catalyst of the invention is as follows. To a suitable reactor are charged 60 grams of ammonium molybdate, 124 grams of 2-ethyl- 1,3-hexanediol, 250 cc. of xylene and 25 cc. of dimethyl formamide. The reactants are heated under reflux with stirrring, and Water is separated from the reflux overhead. The reaction is continued until the rate of water production diminishes, which ordinarily requires from about 5 to 9 hours. The reaction mixture is then cooled, filtered under suction, and added to sufficient solvent neutral mineral oil to give a concentrate calculated to contain about 10 Wt. percent molybdenum. Solvent and catalyst are then removed by reduced pressure distillation at about 160 C. and about 0.25 mm. pressure. The residual product is an additive concentrate which is ready for blending into lubricating oils. While the reaction product could be handled as such, i.e., without diluting it with mineral oil, it is much more convenient to prepare it as a finished mineral oil concentrate containing, say, in the range of 1 to 15 wt. percent of molybdenum.

1 product of Example 1 3 EXAMPLE 2 The reaction of ammonium molybdate with 2-ethyl- 1,3-hexanediol in xylene was conducted in a number of separate preparations wherein in some cases no catalyst 4 Another representative composition is made by adding to a refined mineral lubricating oil sufficient of the product of Example 1 to supply 0.025 weight percent of molybdenum and sufficient sulfurized sperm oil to supwas used and in other cases catalysts of the present invenply the theoretical amount of sulfur to convert molybtion were employed. The reactions were conducted by denum to M08 heating under reflux in the general manner outlined in EX- Various synthetic lubricating oil base stocks may be ample In each Case i reaction Was Continued until used, as well as mineral lubricating oil stocks. The latf rate of Water formatlon f611 Then the p t ter may be of any type including those derived from the in each case was filtered and the amount of filter residue Ordinary paraffinic, naphthenic, asphaltic or mixed base was i g' S E resldlle to tha mineral crude oils by suitable refining methods. Synmonium m0 y a e 6 i t e reaciwn Was use thetic hydrocarbon lubricating oils may also be employed. as a measure of the eificiency of the reaction. The pro- Other synthetic oils include dibasic acid esters such as portions of reactants, the various catalysts used, and the 2 eth 1 h l b t b t t 1 1 t results obtained are given in Table I. It will be seen y eXy car Ona 6 es gyco es ers that with each of the catalysts the reaction time was such as C13 OX0 and dlesters tetraethylene glycol and shortened and more efiicient utilization of the reactants Complex esters as for example the complex 65ml formed was obtained. by the reaction of 1 mole of sebacic acid with 2 moles TABLE I Ammonium Mole Ratio Water Utili- Catalyst Amount of Molybdate, Glycol to Reaction Produced, Residue, g. zation, Catalyst, g. g. Molybdic Time, hrs. cc. Percent Acid 120 1. 0 10. 5 34. 6 49.0 59 120 1. 10. 0 37. 2 44. 0 03 120 1. 25 10.0 33. 5 40. 0 67 23. 7 120 1. 25 9. 0 52. 8 14. 7 88 23. 7 s0 1. 25 4. 5 28. 4 7. 5 s7 23. 7 60 1. 25 5. 5 31. 6 4. 5 92 Pyridine. 24. 5 60 1. 25 6. 5 32. 5 5.1 92 Morpholine 25. 0 50 1. 25 7. 0 31. 1 3. 4 94 1 Utilization based on the weight ratio of residue to charged molybdate.

The reaction products obtained in accordance with this invention may be added as such to lubricating oil compositions to serve as inhibitors of oxidation and corrosion. More preferably they are employed in conjunction with oil-soluble organic sulfur compounds containing labile sulfur that can become available for reaction with the molybdenum to form antiwear agents comprising molybdenum sulfides, as taught in copending application Serial No. 130,263 of John A. Price, filed August 9, 196 1. Sulfur compounds that are suitable for this purpose include: various alkyl and aryl polysulfides such as benzyl disulfide, phenyl disulfide, octyl disulfide, ce'tyl disulfide; sulfurized fatty oils such as sulfurized sperm oil, snlfurized rapeseed oil, sulfurized cotton seed oil; sulfnrized unsaturated alcohols, acids and esters such as sulfurized oleyl alcohol, sulfurized oleic acid, sulfurized isopropyl oleate; thioesters such as C Oxo thioacetate, ethyl dithiohexanoate; alkyl thiophosphoric acid polysulfides such as 'butyl thiophosphoric acid trisulfide; and phosphosulfurized hydrocarbons such as phosphosulfurized polybutene. The sulfur compound should be soluble or dispersible in the lubricating oil composition being used and should be sufficiently nonvolatile that effective quantities will remain in the composition during use.

The sulfur compound is added to the lubricating oil composition in an amount so that sufficient sulfur is present to convert at least half of the molybdenum present to M05 Preferably, at least enough sulfur is provided to convert all of the molybdenum to M08 The molybdenum compound may be added to the lubricating oil composition in quantities to furnish in the range of 0.01 to 1.0 weight percent of molybdenum. The sulfur compound may be added in quantities to furnish in the range of from 0.005 to 5.0 weight percent of sulfur.

A representative lubricating oil composition is made by adding to a high-viscosity-index SAE 10W-30 motor oil, compounded with a polymeric viscosity index improver and a stabilized colloidal barium carbonatephenatc complex, 0.5 weight percent of a phosphosul- :furized terpene and 0.25 weight percent of the reaction of tetraethylene glycol and 2 moles of 2-ethyl hexanoic acid.

The products of the present invention may also be incorporated into diesel fuels in concentrations in the range of 0.0001 to 0.01 weight percent molybdenum to reduce engine wear. It the fuels contain natural sulfur, this will tend to react with the molybdenum compounds to form molybdenum sulfide in situ.

It is to be understood that the examples presented herein are intended to be merely illustrative of the invention and not as limiting it in any manner; nor is the invention to be limited by any theory regarding its operability. The scope of the invention is to be de termined by the appended claims.

What is claimed is:

1. In the reaction of a glycol from the .group consisting of alphaand 'beta-alkane diols of from 2 to 18 carbon atoms with a molybdenum compound selected from the group consisting of molybdic acid, ammonium paramolybdate, ammonium molybdate, M00 and molybdenum pentachloride the improvement which consists in adding to the reacting materials an organic nitrogen base having a boiling point no higher than 300 C. measured at atmospheric pressure and selected from the group consisting of alkyl amines having a total of at least 6 carbon atoms, aryl amines, N-dialkyl amides, azines and oxazines, said nitrogen base being added to the reacting materials in an amount within the range of from 1 to 50 weight percent of the amount of molybdenum compound used in the reaction.

2. Improvement as defined by claim 1 wherein said reaction is conducted in an aromatic hydrocarbon solvent.

3. Improvement as defined by claim 1 wherein ammonium molybdate is reacted with 2-ethyl-1,3-hexanediol.

4. Improvement as defined by claim 1 wherein said nitrogen base is an N-dialkyl amide.

5. Improvement as defined by claim 1 wherein said nitrogen base is morpholine.

6. Improvement as defined by claim 1 wherein said nitrogen base is pyridine.

7. Improvement as defined by claim 1 wherein said nitrogen base is dimethylformamide.

8. An improved process for preparing an organic compleX' containing molybdenum which comprises reacting a glycol selected from the group consisting of alphaand beta-alkane diols of from 2 to 18 carbon atoms with a molybdenum compound selected from the group consisting of molybdic acid, ammonium molybdate, ammonium paramolybdate, molybdenum pentachloride and M at a temperature in the range of from 80 to 160 C. in the presence of an organic nitrogen base having a boiling point no higher than 300 C. measured at atmospheric pressure and selected from the group consisting of alkyl amines having a total of at least six carbon atoms, aryl amines, N-dialkyl amides, azines and oxazines, said nitrogen base being added to the reacting materials in an amount Within the range of from 1 to 50 weight percent of the amount of molybdenum compound used in the reaction, and thereafter removing the organic nitrogen base from the reaction mixture.

9. Improvement as defined by claim 1 wherein the amount of organic nitrogen base is within the range of 10 to weight percent of the amount of molybdenum compound used in the reaction.

10. Process as defined by claim 8 wherein the amount of organic nitrogen base is within the range of 10 to 40 weight percent of the amount of molybdenum compound used in the reaction.

References Cited by the Examiner UNITED STATES PATENTS 2,795,552 6/1957 Abbott et al. 260-429 TOBIAS E. LEVOW, Primary Examiner.

W. J. VAN BALEN, T. L. IAPALUCCI, A. DEMERS, Assistant Examiners. 

1. IN THE REACTION OF A GLYCOL FROM THE GROUP CONSISTING OF ALPHA- AND BETA-ALKANE DIOLS OF FROM 2 TO 18 CARBON ATOMS WITH A MOLYBDENUM COMPOUND SELECTED FROM THE GROUP CONSISTING OF MOLYBDIC ACID, AMMONIUM PARAMOLYBDATE, AMMONIUM MOLYBDATE, MOO3 AND MOLYBDENUM PENTACHLORIDE THE IMPROVEMENT WHICH CONSISTS IN ADDING TO THE REACTING MATERIALS AN ORGANIC NITROGEN BASE HAVING A BOILING POINT NO HIGHER THAN 300*C. MEASURED AT ATMOSPHERIC PRESSURE AND SELECTED FROM THE GROUP CONSISTING OF ALKYL AMINES HAVING A TOTAL OF AT LEAST 6 CARBON ATOMS, ARYL AMINES, N-DIALKYL AMIDES, AZINES AND OXAZINES, SAID NITROGEN BASE BEING ADDED TO THE REACTING MATERIALS IN AN AMOUNT OF MOLYBDENUM COMPOUND WEIGHT PERCENT OF THE AMOUNT OF MOLYBDENUM COMPOUND USED IN THE REACTION. 